Railway traffic controlling apparatus



Jan. 9, 1934. B. E. O'HAGAN ,9 ,6

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 7. 1932 I A! G R] I ,w] .'1 a?" 7 ,10 15 11 INVENTQR. Berna/ a 61019094212.

BY QRW HIS A TTORNE Y Patented Jan. 9, 1934 UNITED STATES PATENT ()FFlCE RAILWAY TRAFFIC CONTROLLING APPARATUS Application September 7, 1932. Serial No. 631,977

3 Claims.

My invention relates to railway traffic controlling apparatus, and more specifically to apparatus for the control of a railway switch motor and for the protection of the switch motor against overload, particularly as applied to systems of the centralized traffic control type.

I will describe one form of switch control and motor overload protection apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view of a remotely located railway switch and the associated control and protection apparatus embodying my invention.

Referring to the drawing, the reference character S designates a railway switch which is actuated by an electric motor M having an armature 1 and a field 2. Operatively connected with the switch is a cutout controller D comprising 20 a contact arm 3 and contacts 4 and 5. Contact 34 remains closed at all times except when the switch occupies its full reverse position, and contact 35 remains closed at all times except when the switch occupies its full normal position. The motor M is controlled in part by contactors N and R which are, in turn, controlled by stick relays N and R respectively. The reference character G designates a code responsive relay which is controlled in any suitable manner by code impulses transmitted from a central control location such as a despatchers office and becomes energized at the end of a normal as well as a reverse switch operating code. Prior to the energization of relay G, other code responsive relays which are not shown, cause battery to be connected to wire N or wire R according as a normal or a reverse switch code is being transmitted.

For providing overload protection to the motor M, use is made of the positive temperature coeflicient resistor F, connected into the motor circuit and bridged by the overload relay E.

To explain the manner in which the apparatus functions, I shall assume that the despatcher wishes to reverse switch S from the normal position in which it is illustrated. To do this, he will send out a suitable code which will first cause battery to be disconnected from wire N and to be connected to wire R, and will then cause relay G to pick up. As soon as relay G picks up, contact 6'? will open, breaking the holding circuit for relay N so that relay N will release. Simultaneously with the opening of contact 6-7, contact 8-9 of relay G will close, and as soon as relay N releases, a pick-up circuit will be closed for relay R which may be A traced from wire R now connected with battery, contact 89 of relay G, wire 10, back contact 11 of relay N wire 12, winding of relay R and wire 13 to the other terminal C of the battery.

As soon as relay R picks up, a pick-up circuit will be closed for contactor R this circuit extending from one terminal B, front contact 14 of relay R wire 15, back contact 16 of relay N wire 17, winding of contactor R wire 18, and

contact 4-3 of controller D to the other terminal C. Contactor R will now pick up to energize motor M for reverse operation of switch S over a circuit extending from one terminal B, resistor F, Wire 19, front contact 20 of contactor R armature 1 of motor M, back contact 21 of contactor N wire 22, and field winding 2 of motor M to the other terminal C of the same source. As soon as the switch S completes its reverse movement, contact 43 of controller D will open, deenergizing contactor R and interrupting the circuit of motor M;

After a reverse switch code has been transmitted to relay G and relay G has become energized, this relay will subsequently release, preparatory to the reception of a normal switch code, but the energized time interval of relay G is suiiiciently long to permit the release of relay N andthe pick-up of relay R When relay G releases, relay R will remain energized over a holding circuit which may be traced from one terminal B, back contact 23 of relay E, wires 24, 26 and 27, front contact 28 of relay R wire 29, contact 930 of relay G, wire 10, back contact 11-of relay N wire 12, winding of relay R and wire 13 to terminal C. Relay R will remain picked up until such time as the despatcher sends out a switch normal code for restoring the switch to the normal position, whereupon relay R will become deenergized at contact 9-30 of relay G, and a pick-up circuit will be closed for relay N at contact 6-31 of relay G. Operation of contactor N and motor M will thereupon follow in the same sequence as already described for the reverse switch movement, the direction of current flow through motor M being now opposite to that existing in the reverse switch operation;

The purpose served by approach locking relays A and A is to prevent a reversal of the switch while an approach section for switch Sis occupied. Should such an approach section be occupied, relay A or A will release, thereby closing a stick circuit for one or the other of the relays N or R depending upon which relay is energized at the time, to prevent release of the relay in question and pick-up of the alternate relay, upon energization of relay G. The condition of relays N and R would therefore remain unchanged following the registry of a switch operating code at relay G, and no response would be ob tainedat motor M and switch S.

To explain the manner in which the overload apparatus functions, I shall assume that an obstruction develops in switch S while the motor is operating in the direction for reverse switch movement, relay R and contactor B being energized. Under this condition, the motor current will rise, heating resistor F and increasing the potential drop across relay E until such time as the current is suflicient to pick up this relay,

thus opening back contact 23. When this occurs,

the holding circuit previously traced for relay R will become interrupted at back contact 23, and

relay R will release, deenergizing contactor R and interrupting the motor circuit. The releasing' time of slow acting relay E is made suinciently long to permit relay R to release before back contact 23 is re-closed. After the motor current is 'interrupted by contactor R relay E will release, re-closing back contact 23, but relay R will not pick up again until the despatcher sends out a switch code for picking up relay G, as before. Therefore, motor M will remain deenergized. This switch code can be either of the switch normal'or switch reverse type, according as the despatcher wishes to move the switch away from the obstruction or to attempt a second switch movement in the original direcion. The cooling time of resistor F is sufficiently rapid to permit the despatcher to attempt a second switch operation immediately following an overload, without danger of picking up the overload relay unless the overload reappears. Due to the time lag obtainable through the use of this temperature coefficient resistor and to the slow pick-up characteristics of relay E, this relay will not'operate upon sudden surges oi motor current of short duration, such as occur at starting, but requires a sustained overload for operation.

It will be understood that instead of the code responsive relay G and the selectively energized wires N and R, any other suitable method for selectively energizing the relays N and R can be used to accomplish the useful object of my invention.

One advantage of apparatus embodying my invention is that the number of wires required between the outlying switch, where relay E and the contactors'll and R are located, and the apparatus group comprising relays N and R is reduced to a minimum, thereby reducing first cost as wellas aiding to prevent dangerous grounds and crosses. At the same time, the apparatus provides a flexible and safe system for the control of remotely located railway switches.

Although I have herein shown and described only one form of switch control and motor overloa'd'protection apparatus embodying my inven- 'tion, it is understood that various changes and modifications may he made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a railway switch, an electric motor for operating said switch, a circuit for operating said motor, a normal and a reverse contactor, means including a front contact of said normal contactor and a back contact of said reverse co'ntactor for energizing said circuit with current of normal polarity to cause said motor to operate said switch to the normal position, means including a front contact of said reverse contactor and a back contact of said normal contactor for energizing said circuit with current of reverse polarity tocause said motor to operate said switch to the reverse position, a first contact governed by said switch which remains closed at all times except when said switch occupies said normal position, a second contact governed by said switch which remains closed at all times except when said switch occupies said reverse position, a positive temperature coeflicient resistor included in said motor circuit, an overload relay connected across a portion of said resistor, a normal and a reverse stick relay, means including a front contact of said normal stick relay and a back contact of said reverse stick relay as well as said first contact for energizing said normal contactor, means including a front contact of said reverse stick relay and aback contact of said normal stick relay as well as said second contact for energizing said reverse contactor, a holding circuit for said normal stick relay including a front contact of said normal stick relay and a back contact of said reverse stick relay as well as a back contact of said overload relay, a holding circuit for said reverse stick relay including a .front contact of said reverse stick relay and a back contact of said normal stick relay as well as said back contact of the overload relay, and means for selectively energizing said normal and said reverse stick relays.

2. In combination, an electric motor, a circuit for reversibly operating said motor, a normal and a reverse contactor, means effective when said normal contactor is energized and said reverse contactor isdeenergized for energizing said'circuit with current of normal relative polarity to operate said motor in the normal direction, means effective when said reverse contactor is energized and said normal contactor is deenergized for energizing said circuit with current of reverse relative polarity to operate said motor in the reverse direction, a normally closed contact governed by the current supplied to said motor in such manner that said contact will open when said current exceeds a predetermined value, a normal and a reverse stick relay, means effective when said normal stick relay is energized and said reverse stick relay is deenergized for energizing said normal contactor, means effective when said reverse stick relay is energized and said normal stick relay is deenergized for energizing said reverse contactor, a holding circuit for said normal stick relay effective when said normal stick relay is energized and said reverse stick relay is deenergized and including said normally closed contact, a holding circuit for said reverse stick relay effective when said reverse stick relay is energized and said normal stick relay is deenergized and including said normally closed contact, and means for selectively energizing said normal and said reverse stick relays.

3. In combination, an electric motor, a circuit for reversibly operating said motor, a normal and a reverse relay, means effective when said normal relay is energized and said reverse relay is deenergized for energizing said circuit with current of normal relative polarity to operate said motor in the normal direction, means effective when said reverse relay is energized and said normal relay is deenergized for energizing said circuit with current of reverse relative polarity to operate said motor in the reverse direction, an

its

by said overload device, a holding circuit for said reverse relay effective when said reverse relay is energized and said normal relay is deenergized and also governed by the same said overload device, and means for selectively energizing said pickup circuits for said normal and said reverse relays.

BERNARD E. OHAGAN. 

